Process for the removal of fatty acids, resins, bitter and mucilaginous substances from fats and oils



H. BOLLMANN.

PnocEss F011 THEIREMovAL 0F PATTY Aclns, Resms, BITTER AND MucILAGINous suBsTANcEs FROM FATS AND OILS.

APPLlcATIon man :uns 22. 1920.

1,371,342, Patented Mr. 15, 1921.

PATENT OFFICE.

UNITED *STATES HERMANN BOLLMANN, 0F HAMBURG, AEBMALNY.

rnocnss ron THE annovA1. or rA'rrY AcIns, nnsms, nrr'rna AND -nucmAerNoUs sUBs'rANcEs raum rA'rs AND ons.

Specification of Letters Patent. Patented Mal- 1-5, 192L Application mea :une 22, 1920. serial No. scossa.

To all lwho/m, it may concern.'

Be it known that I, HERMANN BOLLMANN, a citizen of Hamburg, Germany, residing at Hamburg, Germany, have invented cer tain new and useful Improvements in Processes for the Removal of Fatty Acids, Resins, Bitter and Mucilaginous Substances from Fats and Oils, of which the following is a specification.

It is known to free fats and oils from acids by lixiviation in a counter current process with diluted alcohol of 96 per cent.

' by volume. For the same purpose it has already been proposed to use acetone.

These processes however have notbeen s'uccessful by reason of the 'formation of emul- -sions which it is hardly possible to se arate.

According to the process forming t isinvention the formation of emulsions is coun-A teracted, and the whole of the neutral fat present is recovered with only a small lo.

rIhe lixiviation of the fats and oils is effected by means of solvents capable of miscibility and dilution with water Such as with diluted methyl alcohol, ethyl alcohol, amyl alcohol, acetone or acetic ester which have the power of dissolvingfatty acids and other impurities, but not the neutral oils.

The dilution of the solvent is so chosen as to provide for a sufficient difference between its own specific vity and that of the oil to be purified. he process consists in lixiviating the fats and oils lin successive stages' with one of the solvents in a counter current process in which the oil is separated from the solvent before proceeding to the next stage. E

In every successive sta e the fat repeatedly encounters purer a cobol, acetone or the like. The parts which have gone into solution are se arated from the solvent (for example,by a istillation of the latter) after it has traversed all the stages inthe process. The purified neutralfat and the free f acids are separated from the solvent in fell known manner.

, r carrying the process into effect, use is made 'for example, of a six stage washapparatus with agitating. mechanism and separating vessels interposed between the stages.

lf it is desired to remove the `free fatty acid from 3,060 kg. of rape oil-having a fattyacid content-of 12 percent., use is made for a de-acidiiying agent for example,-

-regulating' cock slowly intel)1 the washm wit acids.

v9,000 kg; of 96 per cent. alcohol.

The oil enters from above by. way Vof a.

a paratus which is fille alcohol, an the agltatmg mechanism ofthe washing apparatus is set in motion. At the same time of three times the quantity, 'that is say alcohol is admitted from below at such a speed that always 1. part of oil and three parts of alcohol enter, the apparatus afresh.

n the uppermost stage the oil and alcohol are thoroughly mixed, after which the mixture enters .at a uniform rate into the sep-- ar'ating vessel situated by the side.

The oiland the alcohol containing the dissolved fatty acids separate themselvesaccording to their specific gravity.

The oil falls tothe bottom of theseparating vessel and then enters into' the. sec-- ond washing stage while the alcohol with the dissolved fatty acids `leaves the se arating vessel and is separated by ation in known manner into alcohol and fatty The. oil washed once in the uppermost stage ows from the separating vessel into thesecond'washing stage where it encounters purer alcohol with which it is mixed, then again passing into a separating vessel from which the oil enters the third washing stage, while the mixture of alcohol and fatty acids passes into the first washing stage, and so on until the oil has reached the lowermost washing sta e in which it is washed with the purest a cohol. rlhe oil then leaves the apparatus for the purpose of being freed from the alcohol disso ved in it in known manner by subsequent distillation.

The process is carried out at a temperature of .QG-30 C. and is cyclic since the alcohol coming from the washing apparatus enters the separating vessel, and after being freed from fatty acids and other impurities, is returned to the washing apparatus.

` lf it be desired to deacidify a hard fat such as cocoanut oil, use is made for example, of an eight stage'washing column without an agitating mechanism but provided with a retarding charge or contrivance such as Raschig rings. The bottom of each stage is so arranged that the specifically heavier Moreover, each stage is equipped for the separation of the alcohol fatty acid mixture. If it is desired to deacidify3,000 kg. of cocoanut oil with a fatty acid content of l5 per cent. it is necessary to use about 10,500 kg. of 92% .methyl alcohol.

The operation is carried out at /l0-50J C. in order that the fat may be maintained in a liquid condition. The column is again recharged with alcohol; the fat enters the uppermost stage at a slow rate, and/three and a half times the quantity of alcohol enters the lowest stage of the column. An intimate contact of the alcohol with the fat takes place at each stage. The fat settles on the bottom of the stage and the mixture of alcohol and fatty acids above it, so that the lighter mixture of alcohol and fatty acids' passes into the upper stage, and the heavier -fat into the lower stage.

Both substances are thus brought into intimate contact in each stage and are so conducted that transition from one stage to another takes place only in separated condition in opposite directions, that is to say, the oil encounters purer alcohol in each suc- 'cessive stage, whereas the alcohol encounters an oil richer in fatty acids at each new stage.

So that by increasing the number of stages on the one hand, the fatty acid can be removed practically in its entirety, while on ghe ther hand the alcohol can be fully utiize The oil flowing away from the column with a little dissolved alcohol, and the alcohol with fatty acid and other impurities removed from the oil are then treated further in known manner.

The fats'and oils purified in this manner are distinguished by extraordinarily high stability, while the alcohol in contradistinc-- tion to alkalis exercises no splitting action on the fatty esters; moreover, the fat splitting enzyms are killed by alcohol.

The accompanying drawing represents a diagrammatic view in section, of apparatus suitable for carrying out the process of the present invention.

In said drawing a, b and o are three cylin-- drical container.; provided near their bottoms with dividin plates d1. In the upper portion of each o the containers are dividing plates d2. The receptacles themselves are preferably filled with suitable filling material such as Raschig rings.

Alcohol, of. the strength above referred to, is run in from the tank e through pipe f into the bottom part of a, said alcohol leaving a through the nipple g and pipe it into thebottank c to the top of Vthe tank I), is again ele-- vated by pump p from the bottom of the tank b to the top of the tank a, and is finally .drawn of through the pipe g. In each of the tanks or containers a', b and c the washing of the oil with the solvent is performed systematically and continuously, wherebyl a very small quantity of alcohol suiiicient for the purification of a large quantity of oil and the alcoholic solution leaving through pipe Zinay pass to a rectifier, and after rectification, may be reintroduced into the tank e.

In each of the tanks a, b and c are provided at about the middle point of the height thereof, valved pipes r1, r2 and r3, re spectively, through which insoluble components and dirty sediments accumulated between the two liquids in the tanks may be drawn off.

I claim A process for the removal of impurities -from fats and oils which comprises passing a. continuous current of diluted solvent of thevimpurities present in fats and oils in one direction through a. systematic leaching apparatus, and passing a `continuous current of oil to be purified in the opposite direction through such system, such oil containing free fatty acid as an impurity, and in each stage of the process passing the said diluted solvent upwardly and passing the oil downwardly through a body of stationary filling` 

